Proposed Concept Two Ns slot, Np pole winding are formed each - - PowerPoint PPT Presentation

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Proposed Concept Two Ns slot, Np pole winding are formed each - - PowerPoint PPT Presentation

Feb 03, 2023 464 likes β€’515 views

Proposed Concept Two Ns slot, Np pole winding are formed each having coil pitch = 2 X slot pitch These two windings (W1, W2) are mechanically phase shifted by an angle To eliminate certain harmonic, this shifting

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  • Two Ns slot, Np pole winding are formed each having coil pitch = 2 X slot pitch
  • These two windings (W1, W2) are mechanically phase shifted by an angle πœ„π‘‘β„Ž
  • To eliminate certain harmonic, πœ‰ this shifting should be selected as πœ„π‘‘β„Ž = 3𝜌/πœ‰
  • Having wye-delta connection within two coils for each of these windings (W1 and W2) make

the current angle electrically 30 degree shifted in time and their positions results 30 degree electrical shift in space. As a result, the resultant MMF for the first sub-harmonics (πœ‰ = 1) becomes zero. It also enhances the torque-producing component.

  • The resultant stator configuration has twice the number of slot compare to their

concentrated wound counterparts which also helps in minimizing cogging torque and this also helps in minimizing torque ripple.

Proposed Concept

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Wye Delta Wye Delta 𝑁𝑁𝐺

1 = 𝑁𝐽 sin π‘™πœŒ

12 sin 𝑙 βˆ’ 1 𝜌 12 sin π‘™πœ„ βˆ’ πœ•π‘’ βˆ’ 𝑙 βˆ’ 1 𝜌 12 𝑁𝑁𝐺2 = 𝑁𝐽 sin π‘™πœŒ 12 sin 𝑙 βˆ’ 1 𝜌 12 sin 𝑙 πœ„ βˆ’ πœ„1 βˆ’ πœ•π‘’ βˆ’ 𝑙 βˆ’ 1 𝜌 12 π‘π‘πΊπ‘ˆ = 2𝑁𝐽 sin π‘™πœŒ 12 sin 𝑙 βˆ’ 1 𝜌 12 sin π‘™πœ„ βˆ’ πœ•π‘’ βˆ’ 𝑙 βˆ’ 1 𝜌 12 βˆ’ π‘™πœ„1 2 cos(π‘™πœ„1 2 )

Ξ /6 2Ξ /6

πœ„1 πœ„1 W1 MMF π‘™πœ„1 2 = 90 𝑝𝑠 270 β‡’ πœ„1 = 77.15 𝑒𝑓𝑕𝑠𝑓𝑓 = 5𝜌 24 + 2.14 W2 MMF To eliminate 7th Harmonics

π‘™πœ„1 2 = 270 β‡’ πœ„1 = 108 =7*pi/24+3

To eliminate 5th Harmonics

Analytical Model

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ΞΈsh (W1 and W2) ΞΈsh (W1 and W2)

W1

W2 W2

W1

Proposed winding Layout Coil configuration

Winding Configuration

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0.25 0.5 0.75 1 1.25 1 5 9 13 17

Harmonics (% relative to main component)

Air-gap MMF Harmonics

Proposed 10P/24S

0.2 0.4 0.6 0.8 1 1.2 1 3 5 7 11 13 17 19

Percentage Relative to the main component Harmonics number

Air-gap MMF Harmonics

Results 10P/12S with wye-delta Conventional 10P/12S (a) (b) (c)

  • From conventional 10P/12S (Fig. a), the first sub-harmonic is eliminated with wye-

delta connection (Fig. b). The torque producing component is also enhanced by 3.5%.

  • From Fig. b, the unwanted 7th harmonic is eliminated by proposed coil shifting
  • concept. This also reduces the higher order harmonics like 17th, 31st, 41st etc.
  • Overall, compare to the conventional 10P/12S winding (Fig. a), the proposed concept

(Fig. c) reduces THD by 61.22% and enhances the fundamental by 1.5%.